Electric pneumatic remote control apparatus



March 2, 1965 L. E,- DONAHUE ELECTRIC PNEUMATIC REMOTE CONTROL APPARATUS Filed Nov. 28, 1961 LAWRENCE $.00 AHUE A 770E105 Y United States Patent 3,171,988 ELECTRIC PNEUMATIC REMOTE CGNTRGL APPARATUS Lawrence E. Donahue, Mount Prospect, Ill., assigncr to Honeywell Inc., a corporation of Delaware Filed Nov. 28, 1961, Ser. No. 155,341 11 Claims. (Cl. 307-144) The subject application relates to an electric pneumatic control and more particularly to a simplified electric pneumatic type of transmission circuit particularly adaptable to remote control applications.

Electric pneumatic control circuits and longline pneumatic transmission circuits are both known and used. The present invention is directed toward a remote control type circuit which utilizes a single pneumatic transmission line with a simplified provision for maintaining a holding circuit type operation at the receiving station and providing for visual indication of the condition of operation of the device to be actuated at the transmitting station. This type of control circuit is particularly applicable in environments Where longline electric transmission is not lfeasible yet electric power is available at the receiving station and possibly at the sending station. While only a single transmitting and receiving station are shown, it will be recognized that a plurality of transmitters and receivers may be utilized where the receiving stations all respond to this same signal and may, if de sired, be sequenced in their operation. It is therefore an object of this invention to provide a simplified electric pneumatic remote control circuit. It is further an object of this invention to provide in an electric pneumatic remote control circuit of this type an apparatus which is selectively operable to provide single, multiple or sequential operations at a remote point with a simplified holding circuit means for maintaining an established condition of operation at the remote point and providing an indication of these operations at the sending station. These and other objects of this invention will become apparent from a reading of the attached description together with the drawing.

The improved electric pneumatic remote control circult of the subject invention is shown in the drawing as including a single transmitting station indicated generally at connected through a pneumatic transmission line indicated generally at 11 to a receiving station indicated generally at 13 which receiving station controls the application of electric power to a device to be operated such as a motor indicated at 15. While a single transmitting station has been shown, it will be recognized that a plurality of transmitters may be utilized connected to the common transmission circuit to selectively apply or control the establishment of a branch pressure in the transmission conduit to con-trol a single or a plurality of receiving units at a single or a plurality of receiving stations and hence a single or plurality of devices can be operated.

The transmitting station shown herein utilizes a push button type controller which is basically a manually operated valve means operative to connect a pneumatic pressure supply such as is indicated at 21 to the transmission conduit and establish a branch line pressure therein or to disconnect the supply conduit 21 from the transmission line and allow air therein to be bled from the transmission conduit to provide a second condition of operation. It will be recognized that this switching device or primary controller may be automatically operable as well as manually operable and may take other forms than a push button type actuator. In the drawing, the push button controller is shown as including a plurality of push buttons or on and off operating mechanisms indicated generally at 25 and 26 which are connected through a linkage and over center mechanism 23 to operate a pivoted lever 21 carrying pins 30 and 31 which engage valve closuremembers 32, 33 respectively through a diaphragm or seallng member 34. The diaphragm defines a pressure chamber Within the switch indicated generally at 35 with one of the valves being connected to the supply conduit 21 through a passage 36 under its seat indicated at 37. This seat 37 and a valve closure member 32 define the valve controlling the inlet or supply pressure to the chamber 35 which chamber is connected to an outlet passage 39 including a restriction 40 and leads to the transm1ss1on conduit 11. A second valve includes the valve closure member 33 and a vlave seat 41 vents the case through a restriction 42, this valve providing a bleed for the chamber 35 and hence the conduit 11 to atmosphere. The respective valve closure members include springs 45 under the closure members tending to urge them in a closed direction and the position of the pivoted lever 29, as positioned by the over center mechanism 28, will determme which of the valves 32, 33 are open. Thus with valve 32, 37 closed, the supply conduit 21 is disconnected from the transmission conduit 11 or is not connected to the pressure chamber 35 within the switch and the conduit 11 is vented through the valve 33, 41 to atmosphere through the restricted vent 42. This will correspond to the operation of the off push button or control 25 which actuates the over center mechanism in such a manner that the lever 35 is so positioned to cause valve operation as described above. The opposite push button 26, as seen in the drawing, will operate the over center mechanism 28 to pivot the lever 29 closing valve 33, 41 and opening valve 32, 39 allowing inlet pressure from the conduit 21 to enter chamber 35 and pass from the chamber 35 through the restricted opening or restriction 40 to the transmission conduit 11 establishing a branch line pressure therein to actuate the remote controller and this will be hereinafter described.

Also positioned at the transmitting station 10 is an indica-ting light indicated generally at 50, this light being controlled by an electric pneumatic transducer 51 which receives its pneumatic signal from the transmission conduit 11 through a branch conduit 52. The transducer 51 includes a pressure responsive means or diaphragm 53 defining a pressure chamber 54 in a casing 55 of the transducer 51 which is connected to the branch conduit 52. The diaphragm acts against a thrust member 56 which engages the operating pin 57 of an on-ofr" switch 58. A return spring 60 positioned within the casing acts against the diaphragm to urge the thrust member 56 in the opposite direction or away from the operating pin 57 of switch 58. The switch 58 connects a source of power indicated by the terminals 61 through a circuit indicated generally at 62 to the indicating light 50 to controllably energize the same from the source 61 when the pin 57 of the switch is engaged and moved to an operative position. When branch line pressure in conduit 11 indicates an operation of the device 15 through operation of the controller 20, the diaphragm 53 in chamber 54 acting against spring 60 of the electric pneumatic transducer responds to a predetermined pressure indicating operation of the device and the switch 58 of the transducer will be operated to energize the indicating light. This indicating light may be remote from or positioned adjacent to the controller 20 but will be related to the transmission portion of the remote control circuit. In the event that an electric source is not available at the transmitting station, on-oft indication can be obtained through a wholly pneumatic device such as a simple pres sure gauge giving an on-off indication instead of a pressure reading.

The transmission line 11 is adapted to extend to the remote location through a single conduit which is easy to install and which permits the use of air rather than electricity for remote control purposes. This type of circuit is particularly adaptable with transmission lines where the environment or atmosphere does not permit the use of electric transmission lines, in installations where pneumatic tubing is already available, and under conditions where the installation of electrical conduits is not feasible, cost and maintenance-wise.

In the present disclosure I have shown a single receiving station although it will be recognized that a plurality of receivers can be operated in a parallel type circuit from a single transmitting station or in other forms later to be described. Thus in the drawing, the receiving station 13 includes a pressure responsive means or motive means 65 which includes a casing 66 having a chamber 67 therein defined by a diaphragm member 70 which chamber 67 is connected to the inlet 71 in the casing which in turn is connected to the transmission conduit 11. The diaphragm 7t) cooperates with a thrust member '75 which actuates a switch 76 or the operating member or pin 77 thereof, this switch being any conventional on-off electric switch. The motive means or pressure responsive means includes a return spring 80 acting against the diaphragm 70 such that the presence or absence of pressure in the chamber 67 will move the operating member 77 of switch 76 between extreme positions and operate the switch in a conventional manner. The pressure required to operate motive means 65 is less than that required for operation of pressure responsive means 51, for purposes to be later noted. While I have shown a switch 76 herein, it will be recognized that in instances where the device to be actuated is a large power consumer, this switch may act as a pilot device operating into a conventional starter. The switch 76 is shown connected to a power source such as is indicated by the terminals 85, through connection 86 from the switch 76 to the device to be operated shown schematically as a motor 15.

The receiving station 13 also includes an electric pneumatic relay 90 which establishes a pneumatic holding circuit for the pressure responsive motive means 65 which acts to raise the pressure in line 11 when the relay is operated. While this relay is shown schematically, it is a conventional unit which includes an energizing coil 91 as part of an electromagnetic structure which is connected to and operates a movable valve element shown in phantom at 94 cooperating with a valve seat 55 also in phantom. The valve portion of this electric pneumatic valve 1 eans is connected through a restriction 150 leading to the transmission conduit 11 and the inlet side of the pressure responsive motive means 65. The valve formed by the closure member 94 and seat 95 operates to connect the transmission conduit and hence the pressure responsive motive means 65 through the restriction 100 to atmosphere such as indicated at 102. The coil 91 of the electric pneumatic valve is connected through conductors 105 in parallel with the device to be actuated 15 and is controlled by the switch 76 upon operation thereof to a closed position. Thus, the electric pneumatic relay is normally open and is closed when the electric circuit is energized. The restriction 100 is of smaller size than the restriction 40 at the transmitting station such that an equilibrium branch pressure or control pressure with a given main or supply pressure may be established sufficient to operate the pressure responsive motive means 65 and actuate the switch 76 and such that the transducer 51 will be operated when the valve of the relay and hence the restriction 100 is closed to atmosphere.

In operation the controller or push button is normally off such that the valve formed by closure member 32 cooperating with seat 39 is closed disconnecting the supply 21 from the transmission conduit 11. The opposite valve formed by the closure member 33 and seat 41 is open providing a passage through the vent 42 through to atmosphere such that the line 11 and chamber is vented. The pressure in chamber 54 of the pressure responsive means 51 controlling the indicating light 50 is also reduced to atmospheric pressure. Thus the indicating light will be oil? and the branch conduit or transmission conduit 11 will be at or near atmospheric pressure due to the vent at the transmitting station and also at the receiving station through the restriction 1M and electric pneumatic relay 90 which is in its open position. Therefore the pressure in chamber 67 of the pressure responsive motive means 65 of the receiving station 13 Will also be at a minimum pressure and the switch 76 will be in an open position. Withthe restrictions and the vents, any change in environment surrounding the transmission conduit will not create pressure at the receiving station to provide a pressure at the receiver which would operate the switch and hence the device in the absence of control pressure.

The primary controller or switch 20 will be operated through manual operation of the respective control button 26 to close the valve 33, 41 and open the valve 32, 37 connecting the supply conduit 21 to the chamber 35 and hence the transmission conduit 11. When valve 33, 41 closes, the vent 42 to atmosphere at the switch or controller is closed and supply pressure is applied to the transmission conduit 11. The pressure responsive con troller 51 controlling the light 50 wil not respond to this pressure to close switch 58 and energize the indicating light at the transmitting station 15 at this time. With pressure applied to the transmission conduit 11, the pres-v sure in chamber 67 of pressure responsive motive means 65 will increase even though the line is bled through the restriction 100 and valve 90 which at this time is not energized. However with correct sizing of the restriction, the pressure buildup in the line will be sufficient to energize the pneumatic actuator or pneumatic motive means 65 which is set to operate at a lower pressure than controller 51 and cause operation of the same to move the switch button 77 of switch 76 causing energization of the device 50 to be operated. With the closure of switch 76 the electric pneumatic valve 90 is energized, closing the vent 162 therethrough to atmosphere through the restriction 100 allowing greater buildup in pressure in the chamber 67 of pressure responsive motive means as to hold the switch in an energized or operated position or condition. This buildup in pressure will be fed back in the line 11 to increase the pressure in chamber 54 of controller 51 at a level to operate the same and turn on the indicating light 50 to indicate that the motor or device 15 is energized. Thus, when switch 20 is actuated, the air feeding through restriction 40 will build up the pressure in conduit 11 high enough to energize switch 76 through the action of actuator 65. When switch 76 energizes and closes solenoid valve 96, the pressure in conduit 11 will go up higher actuating transducer 51 which will light the indicating light 50. This feedback action is accomplished by adjusting transducer 65 to operate at a lower pressure than transducer 51. If the electrical power at plug fails, the solenoid valve will be deenergized, allowing the pressure in conduit 11 to drop to a value low enough to turn off light 50, indicating a power failure at the motor 15.

Where a plurality of receiving stations are utilized, the restriction sizing may be adjusted and varied so that bleed 'theret hr-ough during the energizing phase of operation of the remote control circuit will be held at a level suflicient to operate the respective control devices associated therewith and permit the energization of the holding circuit to eliminate overloading of the power lines when electrical power is regained.

Whenever the remote control circuit is to be deenergized, the primary controller, whether manual or automatic, will be operated to close or out off the pressure supply conduit 21 from the trans-mission conduit 11 and vent the controller Thus in the drawing, the button will be deflected operating the over center mechanism 28 .so that the valve formed by the members 32, 37 will be closed and that for-med by the members 33, 41 will :be opened. This allows a vent under the seat 41 through the passage 102 to communicate with the pressure chamber 35, and the transmission line 11 through the restrict-ion 40. Air will bleed through this restriction at a rate sufiicient to collapse or reduce the pressure in the chamber 54 of the pressure responsive means 51 causing switch 58 to operate to an open position and deenergizing the indicating light 50. At the same time the pressure in the conduit 11 will drop, allowing bleed of the pressure in the chamber 67 of pressure responsive motive means 65 such that the pressure responsive motive means will attain a new condition of operation allowing movement of the actuating button 77 of switch 76 to permit switch 76 to move to an open position deenergizing the device 15 to be actuated and also the electric pneumatic relay 9t) causing an opening of the vent at the receiving station to insure that a pressure responsive motive means will maintain an inactive position.

In considering this invention it should be remembered that the present disclosure is intended to be illustrative only and the scope of the invention should be determined only by the appended claims.

I claim as my invention:

1. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit con nected to at least one transmitting station and at least one receiving station, a pneumatic supply connected to the transmitting station, said transmitting station including valve means which in one position of operation connects said pneumatic sup-ply to said transmission conduit to establish a control pressure therein and in a sec ond condition of operation disconnects said pneumatic supply from said transmission conduit, a first restriction means included in said transmitting station downstream of said valve means, said valve means being operable to provide selectively said conditions of operation, the receiving station including a pres-sure responsive means and an electric switch ope-rated thereby, said switch being adapted to be connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive mean-s to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve mean-s being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated-is energized.

2. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit connected to at least one transmitting station and a plurality 'of receiving stations, a pneuma-tic'supplyconnected to the transmitting station, said transmitting station including valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, a first restriction means included in said transmitting station downstream of said valve means, said valve means being selective-ly operable to provide selectively said conditions of operation, the receiving stations each including a pressure responsive means and an electric switch operated thereby, said switches of said pressure responsive means being connected to devices to be operated and to a source of electric power for controllably energizing said devices to be operated, an electric valve means at each receiving station connected through separate second restrictions to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in said second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said switches of said pressure responsive means to be controllably energized by operation of said switch of said pressure responsive means to close the electric valve means when said devices to be operated are energized.

3. An electric pneumatic remote control apparatus comprising, a single line pneumatic transmission conduit connected to at least one transmitting station and at least one receiving station, a pneumatic supply connected to the transmitting station, said transmitting station including a manually operated valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, a first restriction means included in said transmitting station downstream of said valve means, said valve means being selectively operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an electric switch operated thereby, said switch being connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said switch to be controllably energized by operation of said switch of said pressure responsive means to close the electric valve means when said device to be operated is energized.

4. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit connected to a transmitting station and a receiving station, a pneumatic supply connected to the transmitting station, said transmitting station including a push button type of valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit and vents said transmission conduit to atmosphere, a first restriction means included in said transmitting station downstream of said valve means, said valve means being manually operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an electric switch operated thereby, said electric switch being adapted to be connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized.

5. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit connected to at least one transmitting station and at least one receiving station, a pneumatic supply connected to the transmitting station, said transmitting station including valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, said valve means being selectively operable to said conditions of operation, the receiving station including a pressure responsive means and an electric switch operated thereby, said electric switch being connected to a device to be operated and to a source of electric power for controllably energizing said device to'be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized.

6. An electric pneumaticremote control apparatus com prising, a single pneumatic transmission conduit connected to at least one transmitting station and at least one re ceiving station, a pneumatic supply connected to the transmitting station, said transmitting station including valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, a first restriction means included in said .transmittingstation downstream of said valve means, said valve means being selectively operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an electric switch operated thereby, said electric switch being adapted to be connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized, a second pressure responsive means including a second switch positioned at said transmitting station, said pressure responsive means being connected to said transmission conduit and responsive to a pressure in said conduit indicative of the energization and operation of said electric valve to cause operation of said second switch to a closed position in the presence of said control pressure in said transmission conduit, and indicating light means connected to an electric source of power at said transmission station and controlled by said second switch.

7. An electric pneumatic remote control apparatus comprising, a single line pneumatic transmission conduit connected to a transmitting station and a receiving station, a

pneumatic supply connected to the transmitting station,

said transmitting station including a push button type of valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a first control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit and vents said transmission conduit 'to atmosphere, it first restriction means ineluded in said transmitting station downstream of said valve means, said valve means being manually operable to provide selectively the conditions of operation, the receiving station including a pressure responsive means responsive to said first control pressure and an electric switch operated thereby, said electric switch being adapted to be connected to .3 device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation to establish a second control pressure in said conduit, the electric portion of said electric valve means being connected to said electric source and said switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized, a second pressure responsive means including a second switch adapted to be positioned at said transmitting station, said second pressure responsive means being connected to said transmission conduit to cause operation of the switch of said second responsive means to a closed position in the presence of said second control pressure in said transmission conduit, and indicating light means connected to a source of electric power at said transmission station and controlled by said switch of said second pressure responsive means.

'8. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit'connected to a transmitting station and a receiving station, a pneumatic supply connected'to the transmitting station, said transmitting station including valve means which in one position of operation connects said pneumatic supply to said transmission conduit to-establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, a first restriction means included in said transmitting sta tion downstream of said valve means, said valve means selectively operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an electric switchoperated thereby, said electric switch being connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized, and indicating light means connected to a source of electric power at said transmission station to said transmission conduit to be controlled by the operation of said valve means at said transmission station.

9. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit connected to a transmitting station and a receiving station, a pneumatic supply connected to the transmitting station,

said transmitting station including valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, said valve means being selectively operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an electric switch operated thereby, said electric switch being adapted to be connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric pneumatic holding circuit means including electric valve means to maintain pressure at said pressure responsive means when said electric switch is operated and to release said pressure to atmosphere when said electric switch is not operated, the electric portion of said electric valve means being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized, an electric pneumatic circuit connected to and responsive to the pressure in said transmission conduit upon operation of said holding circuit means, and indicating light means at said transmission station connected to a source of electric power and said electric pneumatic circuit to be controlled by the electric portion of said circuit.

10, An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit connected to at least one transmitting station and at least one receiving station, a pneumatic supply connected to the transmitting station, said transmitting station including valve means which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, a first restriction means included in said transmitting station downstream of said valve means, said valve means being selectively operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an electric switch operated thereby, said electric switch being adapted to be connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure responsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized, and pressure responsive means located at said transmitting station and connected to said transmission conduit being responsive to a rise in pressure in said transmission conduit with operation of said electric valve means at said receiving station.

11. An electric pneumatic remote control apparatus comprising, a single pneumatic transmission conduit connected to at least one transmitting station and at least one receiving station, a pneumatic supply connected to the transmitting station, said transmitting station including valve mean which in one position of operation connects said pneumatic supply to said transmission conduit to establish a control pressure therein and in a second condition of operation disconnects said pneumatic supply from said transmission conduit, a first resFiction means included in said transmitting station downstream of said valve means, said valve means being operable to provide selectively said conditions of operation, the receiving station including a pressure responsive means and an elec tric switch operated thereby, said electric switch being adapted to be connected to a device to be operated and to a source of electric power for controllably energizing said device to be operated, an electric valve means connected through a second restriction to said pressure reponsive means and to atmosphere which in one condition of operation is opened to connect said pressure responsive means to atmosphere and is closed in a second condition of operation, the electric portion of said electric valve means being connected to said electric power source and said electric switch to be controllably energized by operation of said switch to close the electric valve means when said device to be operated is energized, a second pressure responsive means positioned at said transmitting station, said pressure responsive means connected to said transmission conduit and responsive to a pressure in said conduit indicative of the energization and operation of said electric valve to cause operation of its switch to a closed position in the presence of said control pressure in said transmission conduit, and indicating means connected and controlled by said second pressure responsive means.

References Cited by the Examiner UNITED STATES PATENTS 905,378 12/08 Smith 340-229 1,025,559 5/12 Bliss 20083 XR 2,591,118 4/52 Bent 12146.5 3,051,872 8/62 Cowherd 317-123 NEIL C. READ, Primary Examiner. 

1. AN ELECTRIC PENEUMATIC REMOTE CONTROL APPARATUS COMPRISING, A SINGLE PNEUMATIC TRANSMISSION CONDUIT CONNECTED TO AT LEAST ONE TRANSMITTING STATION AND AT LEAST ONE RECEIVING STATION, A PNEUMATIC SUPPLY CONNECTED TO THE TRANSMITTING STATION, SAID TRANSMITTING STATION INCLUDING VALVE MEANS WHICH IN ONE POSITION OF OPERATION CONNECTS SAID PNEUMATIC SUPPLY TO SAID TRANSMISSION CONDUITS TO ESTABLISH A CONTROL PRESSURE THEREIN AND IN A SECOND CONDITION OF OPERATION DISCONNECTS SAID PNEUMATIC SUPPLY FROM SAID TRANSMISSION CONDUIT, A FIRST RESTRICTION MEANS INCLUDED IN SAID TRANSMITTING STATION DOWNSTREAM OF SAID VALVE MEANS, SAID VALVE MEANS BEING OPERABLE TO PROVIDE SELECTIVELY SAID CONDITIONS OF OPERATION, THE RECEIVING STATION INCLUDING A PRESSURE RESPONSIVE MEANS AND AN ELECTRIC SWITCH OPERABLE THEREBY, SAID SWITCH BEING ADAPTED TO BE CONNECTED TO A DRIVE TO BE OPERATED AND TO A SOURCE OF ELECTRIC POWER FOR CONTROLLABLY ENERGIZING SAID DEVICE TO BE OPERATED, AND ELECTRIC VALVE MEANS CONNECTED THROUGH A SECOND RESTRICTION OF SAID PRESSURE RESPONSIVE MEANS AND TO ATMOSPHERE WHICH IN ONE CONDITION OF OPERATION IS OPENED TO CONNECT SAID PRESSURE RESPONSIVE MEANS TO ATMOSPHERE AND IS CLOSED IN A SECOND CONDITION OF OPERATION, THE ELECTRIC PORTION OF SAID ELECTRIC VALVE MEANS BEING CONNECTED TO SAID ELECTRIC POWER SOURCE AND SAID ELECTRIC SWITCH TO BE CONTROLLABLY ENERGIZED BY OPERATION OF SAID SWITCH TO CLOSE THE ELECTRIC VALVE MEANS WHEN SAID DEVICE TO BE OPERATED IS ENERGIZED. 